The present invention relates to a high-voltage circuit breaker having an interrupter unit that can be actuated mechanically, a switch mechanism and a switch rod that is made of an insulating material, that transmits a drive motion, and that is at least partially hollow.
A high-voltage circuit breaker of this type is described in for example, German Utility Model No. G 92 12 434 8 . This reference, describes a tension or pressure rod made of fiber-reinforced insulating material for driving a switch of this type. There the switch rod is made of one piece, connected at its ends with metallic armatures via a glued connection.
In a high-voltage circuit breaker of this sort, there is the problem that for the switching process, very large powers have to be transmitted via the switch rod, so that correspondingly large forces must be transmitted, both as tensile forces and also as pressure forces. In this context, the greatest problems result in the transmission of a pressure motion. If a boundary force that follows from the Euler buckling equation is exceeded, a switch rod can buckle and can be destroyed. Here, according to the theory that the buckling equation fundamentally applies, a sinusoidal oscillation of the switch rod is to be assumed; this rod then buckles in the region of one or several oscillation loops when the boundary force is exceeded.
Conventionally, such a buckling is normally countered by sufficient dimensioning of a switch rod of this sort, or by lateral guides that prevent the buckling through the application of a counterforce.
An object of the present invention is to provide, in a high-voltage circuit breaker, an economical switch rod that nonetheless operates reliably and in particular is also light, in order to keep the masses that are to be accelerated in the switching process low.
This object is achieved in that the switch rod has at least two segments that are pushed into one another in partially overlapping telescoping fashion and are connected with one another, the region in which the segments overlap one another and/or the segment having the larger outer diameter being arranged in the region of the greatest mechanical loading of the switch rod.
According to the present invention, the switch rod is thus assembled from a plurality of segments, such that for example the end segments are not required to receive any particularly large lateral, that is radial, loads. In contrast, the middle region of the switch rod is exposed to greater radial loads, thus, the possibility of buckling is feared. The switch rod can be assembled such that a segment having a larger outer diameter is arranged in this middle region, segment having a higher buckling stability than the regions having a smaller outer diameter. However, it can also be provided that two segments overlap precisely in the middle region of the switch rod, so that the required buckling stability is achieved through the overlapping in this region.
An advantageous construction of the present invention provides that the segments are glued to one another.
By gluing, the rod segments are connected with one another in a constructively simple and reliable fashion.
It can also advantageously be provided that the segments are screwed together.
This type of fastening enables problem-free disassembly of a switch rod.
In addition, it can advantageously be provided that the segments are shrink-fitted to one another.
In this case, it is not necessary to take into account the durability, or material consistency with a rod material, of an adhesive.
Another advantageous construction of the present invention provides that rod segments having an enlarged outer diameter are arranged at the points at which there is a danger of a buckling in the case of a longitudinal compression of the switch rod, in particular according to the Euler buckling equation.
In addition, it can advantageously be provided that the switch rod is made up of three segments, of which the middle segment has an inner diameter that corresponds approximately to the outer diameter of the other two segments, the middle segment forming the middle region of the switch rod.